This tutorial demonstrates how to create a tree to browse points in the DataHub.

Output

Code

/* All user scripts should derive from the base "Application" class */

require ("Application");
require ("WindowsSupport");

/*
 * The real implementation of the point browser is in
 * c:\program files\cogent\opc datahub\require\GPointBrowser.g
 */
 
require ("GPointBrowser");

class TreeViewExample Application
{
    window;
    gtree;
}

/*
 * Specialize the GPointBrowser object so that we get our own callbacks when
 * certain events occur in the point tree.  The default event handling will
 * still be processed to fill the tree as the user traverses it.
 */

class MyGPointBrowser GPointBrowser
{
}

method MyGPointBrowser.OnSelect (pointname)
{
    princ ("Selected: ", pointname, "\n");
}

method MyGPointBrowser.OnDoubleClick(pointname)
{
    princ ("Double Click: ", pointname, "\n");
}

method MyGPointBrowser.OnRightClick(pointname)
{
    princ ("Right Click: ", pointname, "\n");
}

method MyGPointBrowser.OnExpanded (pointname)
{
    princ ("Expanded: ", pointname, "\n");
}

method MyGPointBrowser.OnCollapsed (pointname)
{
    princ ("Collapsed: ", pointname, "\n");
}

/* Write the 'main line' of the program here. */
method TreeViewExample.constructor ()
{
    local   rect = CreateRect (0, 0, 300, 300);
    .window = new GWindow();
    
    .window.Create (0, rect, "GPointBrowser Test", WS_OVERLAPPEDWINDOW, 0);
    .window.CenterWindow();
    .window.GetClientRect (rect);
    .gtree = .window.CreateControl (MyGPointBrowser, 0, 0, rect.right-rect.left,
                                    rect.bottom-rect.top, "Hello world", SS_CENTER);
    .gtree.CenterWindow();
    .gtree.debugging = t;
    .window.MessageHandler (WM_DESTROY, `instance_p(@self) ? destroy(@self) : nil);
    .window.AddControlResizeFlags (.gtree, DLSZ_SIZE_X | DLSZ_SIZE_Y);
    .window.ShowWindow (SW_SHOW);
}

/* Any code to be run when the program gets shut down. */
method TreeViewExample.destructor ()
{
    if (instance_p(.window))
        destroy (.window);
}

/* Start the program by instantiating the class. */
ApplicationSingleton (TreeViewExample);